Demolition hammers are used on work sites to break up hard objects such as rocks, concrete, asphalt, frozen ground, or other materials. The hammers may be mounted to machines, such as back hoes and excavators, or may be hand-held. Such hammers may include a pneumatically or hydraulically actuated power cell having an impact system operatively coupled to a tool. The impact system generates repeated, longitudinally directed forces against a proximal end of a tool disposed inside the hammer housing. The tool extends from the housing to engage the hard object. The forces against a proximal end of a tool are transmitted through the tool to the hard object.
During operation of the hammer, a blank fire may occur. A blank fire refers to when the tool reaches the end of its power stroke without engaging the hard object. When this occurs, the tool abuts a stop and the forces intended to be used to break up the hard object, must be absorbed by the hammer. Buffers used to support the power cell in the housing may absorb some of the forces, while other structural components, such as tie rods, absorb the brunt of the load. Overstressing the tie rods can lead to rod failure, which can cause serious damage to the impact system, including the piston, and other hammer components.